Designing Gestural Interfaces

Chapter 4. Patterns for Free-Form Interactive Gestures

"Sense, sure, you have, Else you could not have motion."

—William Shakespeare, Hamlet, Act III, Scene IV

The following are patterns for gestures that are typically done in space, not via a touchscreen or other interactive surface. Of course, these patterns don't have to be mutually exclusive; free-form and touchscreen patterns can exist on the same device. For instance, a touchscreen kiosk may use Proximity Activates/Deactivates as a way to turn the kiosk on and off.

PROXIMITY ACTIVATES/DEACTIVATES

WHAT

This pattern is for performing the simplest of all gestures, requiring only the presence of a person without any direct body contact (except perhaps to a pressure sensor). When a body is detected, an action triggers.

USE WHEN

Use Proximity Activates/Deactivates to trigger simple on/off settings, such as lighting, display changes, sound, and other environmental controls.

WHY

Environmental and cost-saving concerns have driven the adoption of this pattern. For instance, if lights come on only when a person is in the room, it saves energy (and money).

HOW

The presence of a person can be detected with a variety of means: camera, motion detector, infrared "tripwire," pressure sensor, or microphone.

Of almost all the gestures, this is the one most likely to be triggered accidentally, so care should be taken when calibrating the sensor.

It may be beneficial in certain instances (for privacy or environmental controls) to be able to detect multiple people in one location, which requires considerably more nuance in processing the data.

A variation on this is to change the action based on other (somewhat) detectable characteristics, such as race, age, and gender.^[27] For instance, a store advertisement that utilizes a camera could change its display based on the gender of a passerby.

EXAMPLES

Figure 4-1. Glowing Places combines plastic seating with LED strips and pressure sensors to measure the presence of people over time. Both the number of people sitting and the length of time they stay create lighting effects in the furniture. Many people sitting for brief periods of time result in more active lighting, whereas one or two people sitting for a longer period trigger mellow lighting. Courtesy Philips Lighting.

Figure 4-2. Swinxs is an outdoor game console for children. Several of the games, such as the racing and hide-and-seek games, involve getting close to the base station with the (included) wristband. For example, in the case of a racing game, Swinxs would use the wearer's proximity to the base station to determine the winner. Courtesy Swinxs BV.

Figure 4-3. The Wooden Mirror, which comprises a camera and dozens of individual slats of wood on motors, "reflects" the image of the person standing in front of it. Courtesy Danny Rozen.

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^[27] See, for instance, "Billboards That Look Back," by Stephanie Clifford, in the New York Times, May 31, 2008 (http://www.nytimes.com/2008/05/31/business/media/31billboard.html?ex=1370145600&en=c4fb20d8fbcba416&ei=5124&partner=permalink&exprod=permalink).